1. Field of the Invention
The present invention relates to multi-party conferencing systems.
2. Background Art
A teleconference is the live exchange of information among remotely located devices that are linked by a telecommunications system. Examples of devices that may exchange information during a teleconference include telephones and/or computers. Such conferencing devices may be linked together by a telecommunications system that includes one or more of a telephone network and/or a wide area network such as the Internet. Teleconferencing systems enable audio data, video data, and/or documents to be shared among any number of persons/parties. A teleconference that includes the live exchange of voice communications between participants may be referred to as a “conference call.”
In a large multi-party conference call, multiple conference participants may dial into a central server/switch. The central server/switch typically aggregates the audio that is received from the participants, such as by adding the audio together in some manner (e.g., possibly in a non-linear fashion), and redistributes the audio back to the participants. For instance, this may include the central server choosing the loudest 3 or 4 talkers out of all of the participants, summing the audio associated with the loudest talkers, and transmitting the summed audio back to each of the participant conferencing devices.
In the case of conferences performed over IP (Internet protocol) networks, such server-managed conferences may provide poor audio quality for a number of reasons. For example, in such teleconferencing systems, audio data is encoded at each conferencing device and is decoded at the server. The server selects and sums together some of the received audio to be transmitted back to the conferencing devices. Encoding is again performed at the server to encode the summed audio, and the encoded summed audio is decoded at each conferencing device. Due to this “voice coder tandeming,” where multiple encoding-decoding cycles are performed on the audio data, the conference audio quality may be degraded. Furthermore, the non-linear mixing/selection of the loudest talkers may reduce the conference audio quality. Still further, the difference in volume of audio included in the different audio streams received from the various conferencing devices (e.g., due to quiet talkers sitting far from microphones, and loud talkers sitting close to microphones) can lead to even further reduction in conference audio quality.
As such, the central server (e.g., a single multi-core PC) can become overloaded with the decoding operations performed on each of the received participant audio streams, the re-encoding operation used to encode the summed audio, and further audio processing operations that may be performed, such as automatic gain control (e.g., used to equalize volumes of the different received audio streams). As such, improved techniques for multi-party conferencing are desired that are less complex and provide higher conference audio quality.